(As in the cowboy yell of joy, not the crappy internet company who can't figure out how to effectively update their own IM software)
Mac to Mac works great, Mac to iPhone works great. My kid's on the east coast and I'm going to wake his butt up and tell him to go install it.
Ditto for the gf (for much different reasons)
Publish the open standard
Talk Yahoo into integrating this into their IM...